Issue #3924 has been updated by Xavier Shay.
Actually Luis I just read your gist, my numbers match up with ruby 1.9.3dev (2011-05-28 trunk 31761) [i386-mingw32], I never saw it as bad as 52s for r31496.
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Bug #3924: Performance bug (in require?)
http://redmine.ruby-lang.org/issues/3924
Author: Carsten Bormann
Status: Open
Priority: Normal
Assignee:
Category: core
Target version: 1.9.3
ruby -v: -
=begin
Running irb < /dev/null in 1.9.2 causes 3016 calls to lstat64.
For instance, there is a sequence of 28 repetitions each of lstat calls to all 6 non-empty path prefixes of /opt/local/lib/ruby1.9/1.9.1/irb.rb -- a total of 170 lstats apparently just to load this file; another set of lstats then occurs later for another 18 (times 6) times. Clearly, something is running amok in the calling sequence rb_require_safe -> realpath_rec -> lstat.
Another example: Running a simple test with the baretest gem causes 17008 calls to lstat. According to perftools.rb, 80 % of the 1.2 seconds of CPU is used in Kernel#gem_original_require (and another 12 in GC, some of which may be caused by this).
=end
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